When we see records being broken and unprecedented events such as this, the onus is on those who deny any connection to climate change to prove their case. Global warming has fundamentally altered the background conditions that give rise to all weather. In the strictest sense, all weather is now connected to climate change. Kevin Trenberth

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Tuesday, October 21, 2014

Land and ocean temperature departure from average for September 2014. NOAA

On Monday, we learned from the National Oceanic and Atmospheric Administration that last September was the hottest of them all, out of 135 Septembers going back to 1880.The same was true for August 2014. And June of 2014. And May of 2014. What that means is that for each of these months, the combined, average, global, land and ocean, surface temperature has never been higher, at least since we started recording these temperatures back in the presidency of Rutherford B. Hayes.

These kinds of records are becoming so regular that they're starting to seem a lot less impressive. They're shrug-inducing. But to think of them in that way is a mistake. A little context shows just how dramatic the warming of the globe, on a month-by-month basis, has actually been.

You see, for 355 months now (up through September), "every month on this planet has been warmer than the 20th century average," according to Jessica Blunden, a scientist at NOAA’s National Climatic Data Center. The Post's own Philip Bump, then writing at Grist, pointed out numbers like these back in November 2012, when the streak was only 332 consecutive months -- but since then, every month has just added to the total. And now, we're just shy of 30 years of unbroken warmer-than-average months. The last month that actually was not warmer than the 20th century average, according to Blunden, was February of 1985. (It was merely average, she says.)

If you took out a 30-year mortgage that February, and never refinanced or sold -- but just kept paying the unchanged payment -- you'd have just a few months to go now. And during that entire period of the mortgage, the globe never saw a cooler-than-average month.

Or consider the human lifespan. Right now, in the US, it's 78.7 years. That's just over 944 months. In other words, for more than a third of an average US human lifespan, warmer-than-average months have been the unbroken rule. So will we ever have a colder-than-average month again? Blunden doesn't see it as very likely. "It can happen, but we just haven’t seen it in a long time, and we don’t really expect to see it any time soon," she says. A colder than average year is even less likely.

Granted, it is not as if most Americans actually feelthese steady above-average temperatures, certainly not in a constant way. Nobody actually experiences a global average temperature. Less than a year ago, many of us were freezing amid the descent of the “polar vortex” into the continental US. But that’s local weather. There are constant cold and warm fluctuations in individual places. But warmth has predominated overall.In itsanalysisof 2014 and its amazingly warm temperatures, NOAA also presentsthis figure, which takes a bit of interpreting—but once you figure out the punchline, it’s pretty stunning.

Source: NOAA

The gist here is that 2014 appears reasonably likely to wind up the hottest year on record, in NOAA's accounting. In fact, to tie that record, the remainder of the year merely has to be average for the 21st century.

In climate science circles, there’s already much discussion of the likelihood of 2014 setting a new record. Climate researchers are particularly struck by the fact that prior record years, like 1998 (now the 3rd warmest overall, according to NOAA) have often been El Nino years, which are hotter than average. But so far an official El Nino has not yet been proclaimed.

Thus, a new global average temperature record in 2014 would be all the more extraordinary. So will it happen? "As we watch daily temperature results come in, it’s becoming ever more likely," says John Abraham, a climate scientist at the University of St. Thomas in Minnesota who studies ocean warming and climate change. Abraham emphasizes, though, that there are several other global agencies besides NOAA (including our own NASA) that also track temperatures, and they don't always perfectly agree on the ranking of record years.

"We may break the all-time temperature record without having an El Nino," adds Abraham. "Which means that the Earth shouldn’t be warm this year."

Global warming has often been likened to the situation of a frog in slowly boiling water. We’ve been the frog for almost 30 years.